Dyeing synthetics with soluble leuco ester salts



2,992,062 DYEING SYNTHETICS WITH SOLUBLE LEUCOESTE-R SALTS Henry R. Mautner, Le'onia, and David I. Randall, New Vernon, NJ, assignors to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Nov. 25, 1955, Ser. No. 549,165 6 Claims. ('Cl. 8-35) This invention relates to the dyeing of synthetic fibrous materials, and more particularly to the dyeing of polyacrylonitrile and synthetic linear polyester fibers with vat dyestuffs.

The dyeing of fibrous materials having a basis of polyacrylonitrile or synthetic linear polyesters has for some time been a problem encountered by workers skilled in the art. Various methods and expedients have been proposed for producing dyeings on such fibrous material but the results have not been completely satisfactory. This has been particularly true with respect to attempts made to dye such fibrous material with vat dyestufis. These fibers are well known for their relatively hydrophobic nature whereby an aqueous treatment bath may wet the fibers superficially but has difiiculty penetrating the inside of the fiber. Accordingly, conventional methods for dyeing cotton and other cellulosic materials with vat dyestuffs from an alkaline vat cannot be employed.

It is an object of this invention to produce acceptable dyeings with vat dyestuffs on fibrous material having a basis of polyacrylonitrile or synthetic linear polyesters. Another object of this invention is the provision of a vat dyestuif composition useful for dyeing such fibrous material. Other objects and advantages will appear as the description proceeds.

The above objects are attained by the instant invention which is based upon the discovery that an aqueous dyebath containing a sulfuric acid ester salt of a leuco vat dyestutf, a water-soluble non-ionic surface active agent containing a polyoxyalkylene chain and derived from a reactive hydrogen containing compound, a water-soluble cationic surface active quaternary ammonium compound, and desirably an amide of the type described below, produces commercially acceptable and highly improved pad dyeings of the aforementioned fibrous material. Accordingly, in addition to the aforementioned aqueous dyebath and its method of production, the instant invention includes the improvement comprising the use of such a dyebath for pad dyeing in known manner fibrous material composed of at least 75% by weight of a member of the group consisting of polyacrylonitrile and synthetic linear polyesters.

The above defined non-ionic surface active agents operative in the instant invention may be represented by the general formula wherein R represents the residue of an organic compound containing a reactive hydrogen atom, R represents hydrogen or lower alkyl, and n has a value of from 2 to 100 or more and usually from about 4 to 30. Compounds of this type are well known in the art and are disclosed along with suitable methods for their preparation in numerous patents and other publications. In general, they may be obtained by condensing a polyglycol ether containing the required number of alkenoxy groups or an alkylene oxide such as propylene oxide, butylene oxide, or preferably ethylene oxide, with an organic compoundcontaining a reactive hydrogen atom. As such compounds containing a reactive hydrogen atom there may be mentioned alcohols, phenols, thiols, primary and secondary amines, carboxylic and sulfonic acids and their United States Patent 2,992,062 Patented July 11, 1961 amides. The amount of alkylene oxide condensed with the reactive hydrogen-containing compound, i.e., the length of the polyoxyalkylene chain, will depend primarily upon the particular compound with which it is condensed. As a convenient rule of thumb, approximately 1 mole of alkylene oxide should be employed for each two carbon atoms in the reactive hydrogen-containing compound. However, the optimum amount of alkylene oxide may readily be determined in any particular case by preliminary test and routine experimentation.

The preferred non-ionic surface active agents for use in the instant invention are those derived from alkyl phenolic compounds. Numerous compounds of this type, i.e., polyalkylene oxide derivatives of phenolic compounds containing one or more alkyl substituents, which may be employed in the compositions of the present invention are described in U.S. Patents 2,213,477 and 2,593,112. Those preferred are the water-soluble polyalkylene oxide derivatives of alkyl phenolic compounds in which the total number of alkyl carbon atoms is between 4 and 20. As examples of such phenolic compounds may be mentioned normal and isomeric butyl, amyl, dibutyl and diarnyl phenols and cresols, tripropyl phenols and cresols, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, cetyl, oleyl, octadecyl and the like, phenols and cresols, in addition to dihexyland trihexylphenol prepared from hexene-l and phenol, diisoheptylphenol, dioctyl-phenol, dinonyl-phenol, dioctyl-p-cresol, di-octyl-o-cresol, didecyl-phenol, didecyl-p-cresol, didodecyl-phenol, and the like. Of particular value are the polyalkylene oxide derivatives of secondary and tertiary alkyl substituted phenols and cresols obtained by condensing olefines of the type obtained in petroleum refining with phenols or cresols. In the case of products obtained by condensing phenol or cresol with olefines of from 3 to 5 carbon atoms such as propylene, butylene or amylene, it is desirable to employ the dialkylated phenols or cresols, while in the case of compounds obtained by condensing a phenol or cresol with an olefine containing 8 or more carbon atoms, the mono-substituted derivatives are preferred. Particularly desirable derivatives can be obtainedfrom the phenols and cresols containing a substituent derived from olefins containing from 8 to 18 carbon atoms, such as diisobutylene and, other alkylenes as nonylene, decylene, undecylene, dodecylene, pentadecylen e, octadecylene and mixtures thereof, and may advantageously be the dimers and trimers obtained by polymerization of such low molecular weight olefines as propylene, butylene, isobutylene, amylene or mixtures thereof. However, the Water-soluble polyalkylene oxide derivatives of other organic compounds containing an active hydrogen may be employed in the compositions of the present invention. Thus, the polyalkylene oxide derivatives, described in U.S. Patent 1,970,578, of aliphatic organic hydroxy compounds, carboxy compounds and amino compounds, as well as phenolic compounds, may be employed if desired. As examples of water-insoluble higher fatty acids whose poly-alkylene oxide derivatives may be employed may be mentioned lauric, oleic, ricinoleic, palmitic and stearic acid, and the like, or mixtures thereof, such as the mixtures obtained from animal and vegetable fats and oils or by the oxidation of such petroleum fractions as paraifin wax. There may also be employed polyalkylene oxide derivatives of water insoluble aliphatic hydroxy compounds such as higher aliphatic alcohols, i.e., the alcohols corresponding to the fatty acids specified immediately above, particularly the alcohols obtainable by hydrogenation of the fatty acids or glycerides present in animal or vegetable oils and waxes such as cocoanut oil, castor oil and the like, as well as the polyalkylene oxide derivatives of the animal and vegetable oils, fats and waxes themselves. There may also be used polyalkylene oxide derivatives of organic mercapto compounds such as the products described in U.S. Patent 2,205,021, i.e., the polyalkylene oxide derivatives of such mercaptocompounds as dodecyl mercaptan, oleyl mercaptan, cetyl mercaptan, decyl mercaptan and thiophenols, thionaphthols, benzo-mercaptan, etc.; also the polyalkylene oxide derivatives, such as those described in U.S. Patent 2,085,706, of carboxylic acid amides and of sulfonamides of the type described in U.S. Patent 2,002,- 613, or the polyalkylene oxide derivatives, described in U.S. Patent 2,266,141, of sulfonic acids may be employed if desired. Similarly, the surface active polyalkylene oxide derivatives disclosed in U.S. Patent 2,677,700 may also be employed in the instant invention.

As specific examples of suitable water-soluble non-ionic surface active agents which may be employed in the instant invention, there may be mentioned the reaction product of 1 mole of nonylphenol with 9 to 11 moles of ethylene oxide, the reaction product of 1 mole of castor oil with 20 moles ofethylene oxide, the reaction product of 1 mole of tall oil with 18 moles of ethylene oxide, the reaction product of 1 mole of oleyl alcohol with 20 moles of ethylene oxide, the reaction product of 1 mole of dodecyl mercaptan with 9 moles of ethylene oxide, the reaction product of 1 mole of soyabean oil amine with 10 moles of ethylene oxide, the reaction product of 1 mole of rosin amine with 32 moles of ethylene oxide, the reaction product of 1 mole of cocoanut fatty acid amine with 7 moles of ethylene oxide, and the like. In general, the nonionic agent, or mixtures thereof, should be employed in suflicient amount, and should contain a high enough content of alkyleneoxy groups to yield a stable dispersion, preferably a clear solution of aqueous dyebath. In general, about to oz. of the agent per gallon. of dyebath, or about 4 to 8% by weight of the dyeb'at hsuflicient to yield the desired results.

The water-soluble cationic surface active quaternary ammonium compounds operative in the instant invention are also well known in the art, being generally quaternary ammonium compounds containing at least one high molecular weight radical of at least 8 carbon atoms bonded to the nitrogen atom, and an anion. They may accordingly be represented by the formula wherein A is a high molecular weight radical of at least 8 carbon atoms; R R and R are organic radicals; and X is an anion. -In this formula, the high molecular weight radical A may be saturated or unsaturated and may contain or be interrupted by hetero atoms such as oxygen, sulfur, and nitrogen, aromatic and cycloaliphatic groups, and the like. R R and R are preferably lower molecular weight radicals, although one of them may also be a high molecular weight radical. X in the for mula may be hydroxyl, chloride, bromide, iodide, mono-, dior tribasic phosphate, acetate, formate, lactate, gluconate, sulfate, nitrite, nitrate, cyanide, borate, alkyl sulfate, alkyl or aryl sulfonate, benzoate or the like. As stated above, these compounds are well known and may be produced in known manner, for example by quarternizing a tertiary-amine of the formula NAR R by reaction with a compound having the formula R X. Cationic surface active quaternary ammonium compounds operative in the compositions of the instant invention, and their methods of production are disclosed in the prior art, including U-Si Patents 1,883,042, 2,060,950, 2,086,585, 2,087,131, 2,214,352, 2,309,592 and 2,374,213.

. The preferred quaternary ammonium compounds for use in the compositions of the instant invention are those whereinA is a long chain hydrocarbon radical of from 8 to 18 carbon atoms, as derived for example from cocoanut, palm, soyabean, or castor oil, tallow or the like; R

and R are lower alkylsuch as methyl or ethyl, lower alkylol such as ethanol, or polyoxyalkylene alkanol containing up to 5 oxyalkylene, such as oxyethylene, groups and the like; R is benzyl or lower alkyl such as methyl or ethyl; and X is chloride. The following quaternary ammonium compounds, which may be employed in the instant invention are given for illustrative purposes only: dimethyl-decyl-benzyl-ammonium chloride, dimethyl-dodecyl-benzyl ammonium chloride, diethyl-dodecyl-benz'yl-ammonium bromide; trimethyl-do decyl-arnmonium chloride, allyl-dibutyl-dodecyl ammonium bromide, methyl-diallyl-doclecyl-ammonium iodide, triethyl-dodecyloxymethyl-ammonium chloride, dibenzylhydroxyethyl dodecyloxymethyl ammonium chloride, diethyl-benzylthioethyl-dodecyl-ammonium chloride, diethyl-benzyl-dodecylthioethyl ammonium chloride, dihutyl-allyl-dodecyloxymethyl-ammonium chloride, diethyl cyclohexyl dodecyloxymethyl ammonium chloride, trihydroxyethyl-dodecyl-ammonium chloride, dimethyl-tetradecyl-benzyl-ammonium chloride, diethyl-pentadecyl-benzyl-ammonium bromide, oleyl a ditetraethyleneoxyethanol benzyl ammonium chloride, oleyl ditetraethyleneoxyethanol methyl ammonium sulfate, oleyl hydroxyethyl ethoxyethanol benzyl ammonium chloride, lauryl hydroxyethyl ethoxyethanol benzyl ammo nium chloride, stearyl hyd'roxyethyl ethoxyethanol benzyl ammonium chloride,. stearyl-dihydroxyethyl-benzyl-ammonium chloride, and the like.

In, general, about /2 to 1% ozper gallon (about. 0.4 to- 1.2% by weight) of the quaternary ammonium compound, or mixtures thereof, by weight ofthe dyebath is sufficient to yield the desired results.

The sulfuric acid-ester salts of leuco vatdyestuifs employed in the inst-ant invention are also well known inthe art, being in general available on the. market under, for example, the trademark Algosol (General Aniline & Film Corporation). They may be made by various methods and with the use of various assistants diQQlQSCdIin. the prior The alkali metalsalts, such as those of sodium and potassium,v are usually preferred, although. other. water-soluble or readily water dispersible salts; may be employed such as those with triethanolamine and the like, Illust'ratively, the sulfuric acid ester-salts of the fol? lowing vat dyestuffs, identified in A.A.T.C.C- 1953, may be employed in accordance. withthis'inyention, The. term A,A.T.C.C.'- refers to the Technical. Manual and Year Book ofthe American. Association of Textile Chemistsand Colorists.

Prototype No.

While the exact. nature of the mechanism wherebythe improved resultsof the instant invention are attained isnot fully understood, it is believed thatthereis formed bet'weenthe anionof the ester salt of the leucovat dye-- stuif and the cation of the quaternary ammoniurn comg pound a normally insoluble salt, which is kept dispersedj or in solution in the dyebath by the non-ionic surface" active agent. In the absence of the non-ionic surface active, agent, such salt would precipitate, particularly when the dyebath is hot. Said non-ionic surface active agents do not appear to interfere with the subsequent oxidation of the leuco ester salt with sodium nitrite and acid. The levelness if the dyeings produced is considerably improved as compared with dyeings produced in the absence of the non-ionic surface active agent. In general, the instant invention enables the attainment of more uniform and stable dyebaths, of higher concentrations in addition to more uniform and level dyeings in light to medium shades of high quality as determined by such properties as fastness to light, washing and dry cleaning.

In carrying out pad dyeings with the aqueous dyebaths described above, it was found that the relatively high amounts of non-ionic surface active agent employed in the dyebath caused some undesirable effects, such as undue foaming of the dyebath and undue slippage through the subsequent squeeze rollers caused by reduction of friction. As a further feature of this invention, it has been found that the addition to the dyebath of an N-lower alkyl-2-pyrrolidone, or an N,N-disubstituted formamide such as N,N-dimethyl-, diethyl-, or dihydroxyethyl-formamide, enables a reduction in the amount of non-ionic surface active agent required, whereby the undesirable effects of undue foam and slippage in the squeeze rollers are eliminated. By use of said N-lower; alkyl-2-py-rrolidone or forrnamide compound the amount of quaternary ammonium compound can also be reduced. A further unexpected result of the use of said N-lower alkyl-2-pyrolidone or formamide compound is that a more stable dyebath is produced and the tendency of the salt of the quaternary ammonium compound with the leuco ester salt to precipitate is lessened.

'Ihe N-lower alkyl-Z-pyrrolidones which may be employed in the dyebaths of the instant invention have the formula CH7-CH1 wherein R is an alkyl radical of from 1 to 4 carbon atoms such as ethyl, propyl, isopropyl, butyl, isobutyl and especially methyl. Such pyrrolidones and their methods of production are well known in the art and no claim is made thereto per se.

The N,N-disubstituted formamides which may be employed in the dyebath of the instant invention are likewise well known in the art and no claim is made thereto per se. The N,N-dihydroxy-ethyl-formamide may be readily produced by amidation of formic acid with diethanolamine in known manner.

The N-lower alkyl-Z-pyrrolidone or formamide compound is employed in the dyebath in proportions of about 5 to oz. per gallon, 01' about 4 to 8% by weight, of the dyebath. In conjunction therewith, there may be employed about 2 to 4 oz. per gallon, or about 1.5 to 3% by weight, of the non-ionic surface active agent, and about V2 to- 1 oz. per-gallon, or about 0.4 to 1% by weight, of the quaternary ammonium compound in the dyebath.

The instant invention is applicable to fibrous materials having a basis of polyacrylonitrile in any suitable form as for example in the form of staple or continuous filaments, yarns, slubbings, warps, fibers, and the like. The fiber content may be composed principally of acrylonitn'le homopolymer or of heteropolymers of acrylonitrile and up to 25% by weight of other polymeric material such as vinyl chloride or acetate, styrene,'methacrylic acid, chloroacrylic acid, and their amides, chlorides, nitriles and the like. Other modifying agents may of course be present in the fiber. Such materials, and their methods of production are disclosed for example in US. Patents 2,527,863, 2,548,282, 2,558,735, 2,595,848, etc. Exceptionally good results are obtained in dyeing fibrous materials having a basis of polyacrylonitn'le as available on the market under the trademarks Acrilan (Chemstrand Corporation) and Orlon (Du Pont). Exceptional results are attained with Orlon 81 fiber.

Fibrous materials having a basis of synthetic linear polyesters which may be dyed in accordance with the instant invention and their methods of production are also well known in the art. Such polyester fibers are generally linear condensation polymers of terephthalic acid (or an ester-forming functional derivative thereof) with a polymethylene glycol (preferably ethylene glycol) having up to 10 methylene groups in a chain interconnected to terminal hydroxy groups. Modified or plasticized variations of these fibers may of course also be employed which contain up to 25 of other substances or copolymerized materials, e.g., linear polyesters of ethylene glycol and terephthalic acid (polyethylene terephthalate) which have been modified by the addition of up to 10% of other glycols and/0r dibasic acids or which have been mixed with other materials such as plasticizers, modifiers, etc. Such fibrous materials are available on the market under the trademarks Terylene, Dacron, Fiber V (Du Pont), etc.

The improved aqueous dyebaths of the instant invention are employed in dyeing the aforementioned fibrous materials in accordance with known pad dyeing processes used in applying the leuco ester salts of vat dyestuffs. In preparing the pad liquor, the ester salt of the leuco vat dyestulf is generally first dissolved in hot water, followed by addition of the non-ionic surface active. agent to the dye solution. The solution is then cooled by addition of cold water or otherwise, and the quaternary ammonium compound is then added. The quaternary ammonium compound should not be added to the dyebath before the non-ionic surface active agent, since its salt with the leuco ester salt may precipitate and/or be diificult to redisperse or dissolve even with the use of the non-ionic surface active agent. When an N-lower alkyl- 2-pyrrolidone or formaldehyde compound is employed, it is added to the solution of leuco ester salt in hot water followed by addition of the non-ionic surface active agent and quaternary ammonium compound consecutively in the stated order, or simultaneously as a previously prepared mixture. When using the N-lower alkyl-Z-pyrrolidone or formarnide compound, cooling of the dyebath before addition of the quaternary ammonium compound is not necessary.

Since the process does not operate by exhaustion and the rate of pickup after the squeeze rollers is relatively low being of the order of from about 25 to 60% of liquor by weight of fiber, the concentration of the dye stuff in the dyebath must be selected accordingly to give the desired depths of shade. In general, from about 1 to 8 oz. of dyestuff (as commercially available) per gallon (about 0.75 to 6.0% by weight) of pad liquor is sufficient to achieve the desired results. Oxidizing agents effective for converting the leuco ester salts to their final keto form should not be added to the pad liquor in view, of the presence therein of the quaternary ammonium compound, but must be applied in known manner in a subsequent developing step. Oxidation may be carried out in usual manner, for example, by passage through an approximately 2% sulfuric acid (by volume) solution containing about 3.5 to 4 g. per gallon of sodium nitrite. The fibrous material is then rinsed, and scoured in the presence of a detergent and/or soda ash or equivknown dye and development assistants, manipulative pro- 7 ced'ures, and the like. The following examples, in which parts are by weight unless otherwise indicated, are illustrative of the instant invention and are not to be regarded as limitative. The non-ionic surface active agent employed in the examples is the condensation product of 1 mole of nonylphenol with about 10 to 11 moles of ethylene oxide. The cationic quaternary ammonium agent employed in the examples is the condensation product of 1 mole of cocoarnines with about 3 moles of ethylene oxide, quaternized by reaction with about equimolar amounts of benzyl chloride. Said cocoamines comprise a mixture of about 8% octylamines, 9% decylamines 47% dodecylamines 18% tetradecylamines, 8% hexadecylamines, octadecylamines and 5% octadecenylamines. The condensation product of these amines will accordingly comprise a mixture of quaternary ammonium compounds, each molecule of which probably consists of an N-ethanol-N-ethoxy-ethanol benzyl ammonium chloride containing as an N-substituent the residue of the respective cocoamines.

Example 1 An aqueous pad liquor isprepared by dissolving Algosol Red IFBB in hot water in proportions of about 1.5 oz. per gallon. The non-ionic surface active agent is then dissolved in the dyebath in proportions of about 6 oz. perv gallon after which the dyebath is cooled by addition. of cold water and the cationic quaternary ammonium agent mixed into the dyebath in proportions of about 1 oz. per gallon. A strip of Orlon 81 (polyacrylonitrile). fabric is padded with the resulting dye liquor at. 1:40 to 150 F. and dried. The dyeing is then developed by passing the fabric through a 2% sulfuric acid solution (by volume) containing about 3.8 g. of sodium nitrite per gallon at 140 F., rinsed with hot water, and scouredwith a detergent solution in the presence of soda ash at 140 F. for 10 minutes. A uniform, level, pinkish-red dyeing is produced having good light fastness and resistance to dry cleaning at room temperature and excellent resistance to washing.

Similarresults are obtained when the process of this example is employed. for dyeing a strip of synthetic linear polyester fabric (Dacron) and Acrilan (modified polyacrylonitrile) Example 2 An aqueous pad' liquor is prepared by dissolving Algosol Green IBW Paste in hot water in proportions of about 1.5 oz. per gallon. N-methyl-2-pyrrolidone is then mixed into the dyebath in proportions of about 6 oz. per gallon. To the dyebath is then added non-ionic surface active agent in proportions of about 3 oz. per gallon and cationic quaternary ammonium agent in proportions of about oz. per gallon, as a previously prepared mixture. Dyeing of a strip of Orlon 81 fabric and developing is then carried out in the same manner as described in Example 1. A uniform, level, light-medium green dyeing having good light fastness and resistance to dry cleaning at room temperature and excellent resistance to Washing is produced.

Similar results are obtained when the process of this example is employed for dyeing a strip of synthetic linear polyester fabric (Dacron) and Acrilan (modified pol'yacrylom'trile) Example 3 The procedure of Example 2 is repeated, but employing N,N-dimethyl-formamide instead of N-methyl-Z-pyrrolidone. Similar results are obtained in dyeing the same fabrics.

Example 4 The procedure of Example 2 is repeated but employing N,N dihydroxyethyl-formamide instead of N-methyl-Z- p'yrrolidone;

wanes Example 5 l The procedure of. Example 2 is repeated, but employing N,N-diethyl-formamide instead of N-methyl-Z-py-rrolidone.

Example 6 In a mill run, an aqueous pad liquor is prepared by dissolving Algosol Brown IBR in hot water in proportions of about 3.0 oz. per gallon. N-methyl-Z-pyrrolidone is then mixed into the dyebath in proportions of about 6 oz. per gallon. To the dyebath is then added non-ionic surface active agent in proportions of about 3 oz. per gallon and cationic quaterenary ammonium agent in proportions of about 0.5 oz. per gallon, as a previously prepared mixture. A 300 yard strip of fabric containing about 75% Orlon 81 fibrous material and 25% nylon in stripes, previously dyed by the top chrome method with Chromogene Black -ETO (General Aniline & Film Corporation; Cl. 203) whereby only the nylon is dyed black, is padded with the above described aqueous pad liquor at to F. with a pressure of 6- tons. The dyed fabric is then subjected to an air drying operation on a covered tenter frame for 44' seconds at 360 F., corresponding to a speed of about 36 yards per minute. The dried fabric is then developed on a padder at 140 to 150 F. with a solution containing 32 lbs. of concentrated sulfuric acid and 14 oz. of sodium nitrite per 100 gallons, with subsequent skying, followed by hot rinsing and scouring in a 2% soda ash solution at F. A uniform, level, tan dyeing is obtained on the Orlon 81 fibrous material which is of high quality and commercially acceptable. It has good to excellent properties when tested by the A.A.T.C.C. wash test No. 3, acid and alkaline perspiration tests, dry cleaning and crock fastness tests, and 20 and 40 hr. tests in the Fadeometer.

Example 7 The process of Example 6 is repeated, but employing, per gallon, about 1.5 oz. of Algosol Blue IBC Paste, 0.3 oz. of Algosol Olive Green IB, and 0.12 oz. of Algosol Red IFBB instead of 3.0 oz. per gallon of Algosol Brown IBR. A uniform, level, ligh blue dyeing of similar quality and properties is obtained.

Example 8 The process of Example 6 is repeated, but employing, per gallon, about 2.0 oz. of Algosol Grey IBL, 0.6 oz. of Algosol Brown IBR, and 0.4 oz. of Algosol Olive Green IB, instead of 3.0 oz. per gallon of Algosol Brown IBR. A uniform, level, light grey dyeing of similar quality and properties is obtained.

This invention has been disclosed with respect to certain preferred embodiments, and various modifications and variations thereof will become obvious to those skilled in the art. It is to be understood that such modifications and variations are to be included. within the spirit and purview of this application and the scope of the appended claims.

We claim:

1. An. aqueous dyebath containing a sulfuric acid ester salt of a leuco vat dyestulf and, by weight, about 4 to 8% of a water-soluble nonionic surface active agent containing a polyoxyethylene chain and derived from a compound containing at least 10 carbon atoms and a reactive hydrogen atom, and about 0.4 to 1.5% of a water-soluble cationic surface active quaternary ammonium compound containing an aliphatic hydrocarbon radical of from 8 to 18 carbon atoms.

2. In a process wherein fibers composed of at least 75% by weight of a member of the group consisting of polyacrylonitrile and synthetic linear polyesters of terephthalic acid witha polymethylene glycol are dyed by padding with an aqueous bath containing a sulfuric acid ester salt of a leuco vat dyestufl, the improvement comprising employing as such dyebath a dyebath as defined in claim 1.

3. A dyebath as defined in claim 1 wherein said nonionic surface active agent is the condensation product of 1 mole of nonylphenol with about 10 to 11 moles of ethylene oxide.

4. A dyebath as defined in claim 1 wherein said quaternary ammonium compound is the condensation product of 1 mole of cocoamines with about 3 moles of ethylene oxide quaternized with about equimolar amounts of benzyl chloride.

5. In a process wherein fibers composed of at least 75% by weight of a member of the group consisting of polyacrylonitrile and synthetic linear polyesters of terephthalic acid with a polymethylene glycol are dyed by padding with an aqueuos bath containing a sulfuric acid ester salt of a leuco vat dyestufi, the improvement comprising employing as such dyebath a dyebath as defined in claim 3.

6. In a process wherein fibers composed of at least 75% by weight of a member of the group consisting of polyacrylom'trile and synthetic linear polyesters of tereph- 10 thalic acid with a polymethylene glycol are dyed by padding with an aqeous bath containing a sulfuric acid ester salt of a leuco vat dyestuff, the improvement comprising employing as such dyebath a dyebath as defined in claim 4.

References Cited in the file of this patent UNITED STATES PATENTS 2,228,369 Schoeller Jan. 14, 1941 2,569,470 Hagemeyer Oct. 2, 1951 2,646,339 Ward July 21, 1953 2,794,015 Jackson et a1. May 28, 1957 2,890,092 Mau-tner June 9, 1959 FOREIGN PATENTS 333,147 Great Britain July 30, 1930 497,779 Canada Nov. 17, 1953 765,335 Great Britain Jan. 9, 1957 OTHER REFERENCES Chemical Industries for March, 1943, pp. 326328. American Dye Reporter for November 13, 1950, p. 790.

UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2,992,062 July 11, 1961 Henry R. Mautner et al It is hereby certified that error appears in the above numbered patent requiring correction and 'that the seidLetters Patent should read as corrected below.

Column 6, line 41, for "formaldehydeVread formamide Signed and sealed this 3rd day of April 1962.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Commissioner of Patents Attesting Officer 

1. AN AQUEOUS DYEBATH CONTAINING A SULFURIC ACID ESTER SALT OF A LEUCO VAT DYESTUFF AND, BY WEIGHT, ABOUT 4 TO 8% OF A WATER-SOLUBLE NONIONIC SURFACE ACTIVE AGENT CONTAINING A POLYOXYETHYLENE CHAIN AND DERIVED FROM A COMPOUND CONTAINING AT LEAST 10 CARBON ATOMS AND A REACTIVE HYDROGEN ATOM, AND ABOUT 0.4 TO 1.5% OF A WATER-SOLUBLE CATIONIC SURFACE ACTIVE QUATERNARY AMMONIUM COMPOUND CONTAINING AN ALIPHATIC HYDROCARBON RADICAL OF FROM 8 TO 18 CARBON ATOMS.
 2. IN A PROCESS WHEREIN FIBERS COMPOSED OF AT LEAST 75% BY WEIGHT OF A MEMBER OF THE GROUP CONSISTING OF POLYACRYLONITRILE AND SYNTHETIC LINEAR POLYESTERS OF TEREPHTHALIC ACID WITH A POLYMETHYLENE GLYCOL ARE DYED BY PADDING WITH AN AQUEOUS BATH CONTAINING A SULFURIC ACID ESTER SALT OF A LEUCO VAT DYESTUFF, THE IMPROVEMENT COMPRISING EMPLOYING AS SUCH DYEBATH A DYEBATH AS DEFINED IN CLAIM
 1. 